1. Technical Field
This invention relates to the design of communications networks and in particular to methods and apparatus for evolving a design for a network using a technique involving evolution of design rules.
2. Related Art
Design of a network architecture and configuration is a complex task, especially in respect of large data networks having, or likely to require, a large number of nodes and interconnecting links.
A wide range of different systems have been devised to assist in the design of network architectures and configurations. A number of such systems are based upon the idea of using an expert system comprising a database of rules to be applied to a particular network design problem, be it the design of a new network or the modification of an existing network to meet a set of customer requirements, for example a rising demand for peak traffic capacity.
International patent application PCT/US96/09899 of Cooper et al. describes a system for selecting options for modifying a network architecture in accordance with user preferences and predetermined traffic requirements, using a knowledge base of rules. Beginning with a baseline network architecture, rules from the knowledge base are used to select different categories of modification that may be made to the baseline architecture, at the same time satisfying the user preferences, and a network simulator simulates operation and performance of modified networks in each category according to the predetermined traffic requirements. Particular modification options in one or more categories are then selected using rules from the knowledge base, taking account of performance results from the network simulations and the user preferences. Further simulation of each of the selected modification options is then used to assess their performance and cost relative to the performance and cost of the baseline architecture and so produce a ranked list of options for a modified network architecture.
While a great deal of experience may be embodied a knowledge base of rules for use in such systems, the resultant options for modification of a network are nevertheless limited by the rule set used to devise them.